The invention relates to a process for isomerizing hydrocarbons, preferably normal paraffins, in the presence of a zeolite catalyst composition to isomerized hydrocarbons, preferably iso-paraffins.
The invention also relates to an improved method of making a zeolite catalyst composition having improved properties when compared with certain other zeolite catalyst compositions.
It is known that in a hydrotreating process for treating a hydrocarbon-containing fluid, such as catalytically cracked gasoline or gasoline range naphtha, the content of sulfur impurities is generally reduced thereby producing a hydrotreated product that can be commercially used. However, most commercial hydrotreating processes, contemporaneous with the reduction of sulfur content, also reduce the octane number of the hydrotreated product. Therefore, a second reforming/isomerization process is generally required to increase the octane number. Normal paraffins, also referred to as n-paraffins, are a major low-octane number contributor among the products of a hydrotreating process, e.g., among the products of hydrotreating catalytically cracked gasoline. However, conventional reforming/isomerization catalysts promoted by noble metals are unable to upgrade the n-paraffins of gasoline range naphtha due to the high sulfur environment.
It is therefore desirable to minimize the octane loss during the hydrotreating process by developing a catalyst which can be used subsequent to the hydrotreating process to enhance octane number. There is also a need to develop a catalyst which can be used to isomerize the n-paraffins in the product produced from such hydrotreating process, preferably the isomerization of n-hexane to iso-hexanes, i.e., C.sub.6 isomers, such as dimethyl butanes (which includes 2,2-dimethyl butane and 2,3-dimethyl butane), methyl pentanes (which includes 2-methyl pentane and 3-methyl pentane), and the like and combinations thereof. Such development would also be a significant contribution to the art and to the economy.